The invention relates generally to mounting structures for outboard motors, especially electric trolling motors of the type that are commonly mounted on the bow of a fishing boat. The electric trolling motor is generally suspended beneath the surface of the water from a mounting structure that is attached to the bow of the boat. There are known and used various different types of mounting brackets, but the usual structure is to suspend the electric motor and the propeller driven by it at the bottom end of a vertical tube that is gripped by a portion of the mounting bracket. Since the electric trolling motor is beneath the surface of the water, it not infrequently happens that the motor will strike a submerged object which can cause damage to the motor and to the mounting structure.
In order to minimize the damage to the motor and mounting structure, a variety of different mounting structures have been developed over the years in an attempt to absorb the shock of the motor striking an underwater object. A recent design of this general type is shown in U.S. Pat. No. 4,555,233, issued Nov. 26, 1985 to Mark S. Klammer and Del P. Decko for their invention entitled "Shock-Absorbing Bow Mount for Trolling Motors". The device disclosed in this patent has an array of four springs, two upper springs and two lower springs which surround pins interconnecting the motor mounting structure with the mounting bracket that is affixed to the boat. With the structure disclosed in this patent, when the impact is from either direction, either the upper or lower springs will serve as shock absorbers. However, the patent merely describes a shock-absorbing structure and does not permit the submerged electric motor to move through a very wide range and thus move over and out of the way of a submerged object. Moreover, when in normal operating position, there is no positive connection between the mounting structure for the motor and the mounting structure affixed to the boat. In effect, the structure shown in this patent is in reality merely a shock absorbing structure and does not permit any actual release of the motor from its mounting structure on the boat whenever a submerged object is struck.
Other patents of the prior art, many of which are listed in U.S. Pat. No. 4,555,233 allow pivoting movement of the electric trolling motor when a submerged object is struck in one direction but not when the boat is moving in the other direction. Also, none of these prior art patents disclose a structure which permits a wide range of pivoting combined with an automatic reset to the normal operating position.
There is therefore a need for an improved mounting structure for an electric trolling motor which permits the motor to move over a submerged object when struck regardless of the direction or travel of the boat, and a structure which will permit the mounting structure to return to its normal operating position automatically and thereafter provide a positive drive between the motor and the boat.